In-vehicle device, method, computer program, driving assistance server, and driving assistance method

Abstract

This in-vehicle device comprises a wireless communication device, a driving assistance device for assisting in driving of a vehicle by using driving assistance information received from an external server through the wireless communication device, an operation determination unit that determines whether or not the in-vehicle device is to operate in place of the external server in response to reception of a request for distributing driving assistance information from another in-vehicle device, and an assistance information transmission device that transmits, if the result of determination by the operation determination unit is affirmative, driving assistance information for the vehicle available to the in-vehicle device to another in-vehicle device through the wireless communication device.

Description

[Technical Field]

[0001] This disclosure relates to an in-vehicle device, a method, a computer program, a driving assistance server, and a driving assistance method. This application claims priority to Japanese Application No. 2021-110815 filed on July 2, 2021, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] Connected services based on road-vehicle cooperation are being provided to assist vehicle driving. For example, they provide driving assistance at intersections based on dynamic maps created using information from infrastructure sensors, such as roadside cameras and LiDAR (Light Detection and Ranging), and vehicles. The dynamic map is created based on data collected from infrastructure sensors and vehicles in the area where the vehicle is traveling, by an edge server located to enable high-speed communication with the infrastructure sensors and vehicles on the road. The dynamic map is placed in each vehicle, and the onboard device installed in each vehicle provides driving assistance using the dynamic map according to the functions equipped in each vehicle.

[0003] In such a road-vehicle cooperative system, if communication with the server is interrupted or the server breaks down, the vehicle cannot obtain the dynamic map. As a result, there is a problem that driving assistance cannot be provided to each vehicle. Therefore, measures are needed to deal with the situation when communication with the server is interrupted or the server breaks down.

[0004] One proposal to solve this problem is disclosed in Patent Document 1, which is listed below. The technology disclosed in Patent Document 1 provides a redundant communication path between the vehicle and the server in case communication between the vehicle and the server is interrupted or information from the server to the vehicle is lost. To this end, the technology disclosed in Patent Document 1 provides multiple communication devices, including those for vehicle-to-vehicle communication, in the vehicle. When communication between the vehicle and the server is interrupted, the on-board device installed in the vehicle searches for other vehicles to which communication data from the server can be transferred, receives the data via vehicle-to-vehicle communication, and uses the data for driving assistance. A nearby vehicle that receives a search signal from another vehicle determines whether communication data from the server can be transferred, and if so, initiates communication. Even if communication is not possible, the nearby vehicle transmits a message to that effect to the vehicle that sent the search signal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-162031 A Summary of the Invention [Means for solving the problem]

[0006] An in-vehicle device according to a first aspect of the present disclosure is an in-vehicle device including a wireless communication device and a driving assistance device for providing driving assistance to a vehicle using driving assistance information received from an external server via the wireless communication device, and further including an operation determination unit that determines whether the in-vehicle device should operate in place of the external server in response to receiving a request for distribution of driving assistance information from another in-vehicle device, and an assistance information transmission device that transmits driving assistance information of the vehicle that can be used by the in-vehicle device to the other in-vehicle device via the wireless communication device when the determination by the operation determination unit is positive.

[0007] A method for operating an in-vehicle device according to a second aspect of the present disclosure includes the steps of: a computer providing driving assistance to a vehicle using driving assistance information received from an external server via a wireless communication device; a computer determining whether or not the computer should operate in place of the external server in response to receiving a request for distribution of driving assistance information from another in-vehicle device; and a computer transmitting driving assistance information that can be used by the computer to the other in-vehicle device via the wireless communication device when the determination in the determination step is positive.

[0008] A computer program according to a third aspect of the present disclosure causes a computer connected to a wireless communication device to function as a driving assistance device for providing driving assistance to a vehicle using driving assistance information received from an external server via the wireless communication device, an operation determination unit that determines whether the computer should operate in place of the external server in response to receiving a request for distribution of driving assistance information from another in-vehicle device, and an assistance information transmission device that transmits assistance information that the computer can use to the other in-vehicle device via the wireless communication device when the determination by the operation determination unit is positive.

[0009] A driving assistance server according to a fourth aspect of the present disclosure is a driving assistance server that creates driving assistance information within a management area and transmits it to vehicles within the management area, and includes: a driving assistance information creation unit that receives sensor data from a sensor that detects traffic conditions in the management area and creates the driving assistance information; an alternative server vehicle list creation unit that collects vehicle information regarding vehicles present within the management area and creates an alternative server vehicle list that is a list of vehicles that can operate as alternative servers for the driving assistance server; and a transmission device that adds the alternative server vehicle list to the driving assistance information and transmits it to vehicles.

[0010] A driving assistance method according to a fifth aspect of the present disclosure is a driving assistance method in a driving assistance system including a driving assistance server for creating driving assistance information within a management area and transmitting it to vehicles within the management area, and includes the steps of a computer receiving sensor data from a sensor that detects traffic conditions in the management area and creating driving assistance information, a computer collecting vehicle information regarding vehicles present within the management area and creating an alternative server vehicle list that is a list of vehicles that can operate as alternative servers for the driving assistance server, and a computer adding the alternative server vehicle list to the driving assistance information and transmitting it to the vehicles.

[0011] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the configuration of a driving assistance system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing a functional configuration of the in-vehicle device according to the embodiment of the present disclosure. [Figure 3] FIG. 3 is a block diagram showing the functional configuration of the mini edge server shown in FIG. [Figure 4] FIG. 4 is a block diagram showing a functional configuration of the mini edge server initialization unit shown in FIG. [Figure 5] FIG. 5 is a block diagram illustrating a functional configuration of the edge server shown in FIG. [Figure 6] FIG. 6 is a flowchart of the program executed by the alternative server. [Figure 7] FIG. 7 is a flowchart of a program executed by the in-vehicle device shown in FIG. [Figure 8] FIG. 8 is a flowchart of a program executed by the in-vehicle device shown in FIG. [Figure 9]FIG. 9 is a flowchart of a program that realizes the mini edge server initialization unit shown in FIGS. [Figure 10] FIG. 10 is a flowchart of a program executed by the cooperation control ECU (Electronic Control Unit) shown in FIG. [Figure 11] FIG. 11 is a flowchart of a program executed by the transfer unit shown in FIG. [Figure 12] FIG. 12 is a flowchart of a program for realizing the mini edge server shown in FIGS. [Figure 13] FIG. 13 is a flowchart of a program executed by the cooperation control ECU shown in FIG. [Figure 14] FIG. 14 is a diagram for explaining the second embodiment of the present disclosure. [Figure 15] FIG. 15 is a diagram showing a graph for determining a target region in the second embodiment. [Figure 16] FIG. 16 is a block diagram showing the functional configuration of the edge server in the second embodiment. [Figure 17] FIG. 17 is a flowchart of a program executed by the edge server in the second embodiment. [Figure 18] FIG. 18 is a block diagram showing the hardware configuration of the edge server in the first and second embodiments. [Figure 19] FIG. 19 is a block diagram showing a network configuration in a vehicle equipped with an on-board device according to the first and second embodiments. [Figure 20] FIG. 20 is a block diagram showing a schematic hardware configuration of the in-vehicle device. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Problem this disclosure aims to solve] In the technology described in Patent Document 1, a vehicle searches for a replacement vehicle after communication with the server is interrupted. Therefore, it is difficult to apply the technology described in Patent Document 1 to driving assistance that requires high real-time performance, such as sharing dynamic maps. In the first place, there is also the problem that if the server breaks down, driving assistance information cannot be obtained from any route. Therefore, there is a demand for technology that is highly real-time and allows as much driving assistance information as possible to be obtained.

[0014] An object of this disclosure is to provide an in-vehicle device, method, computer program, driving assistance server, and driving assistance method that are highly real-time and enable the acquisition of driving assistance information as much as possible.

[0015] [Effect of this disclosure] According to this disclosure, it is possible to provide an in-vehicle device, method, computer program, driving assistance server, and driving assistance method that are highly real-time and allow the acquisition of driving assistance information as much as possible.

[0016] [Description of the embodiments of the present disclosure] In the following description and drawings, the same parts are designated by the same reference numerals, and therefore detailed descriptions thereof will not be repeated. Note that at least a part of the following disclosure may be combined in any desired manner.

[0017] (1) An in-vehicle device according to a first aspect of the present disclosure includes a wireless communication device and a driving assistance device for providing driving assistance to a vehicle using assistance information for assisting driving received from an external server via the wireless communication device, and includes an operation determination unit that determines whether the in-vehicle device should operate in place of the external server in response to receiving a request for distribution of assistance information from another in-vehicle device, and an assistance information transmission device that transmits vehicle assistance information that can be used by the in-vehicle device to the other in-vehicle device via the wireless communication device when the determination by the operation determination unit is positive.

[0018] When the in-vehicle device is receiving assistance information from an external server and communication is interrupted, the operation determination unit determines whether the in-vehicle device should operate in place of the external server. If it determines that the in-vehicle device should operate, the assistance information transmission device transmits assistance information that can be used by the in-vehicle device to other vehicles. Other vehicles that cannot communicate with the external server can provide driving assistance using the assistance information transmitted from this vehicle. In this case, there is no need to search in advance whether this vehicle can operate as a server. As a result, even if a failure occurs in the external server, driving assistance can be immediately continued in many vehicles.

[0019] (2) The assistance information received by the driving assistance device from the external server may include the driving assistance information and a list of vehicles that can operate as an alternative server, and the operation determination unit may include a list inquiry unit that queries the list and determines whether the vehicle equipped with the in-vehicle device should operate in place of the external server based on whether the vehicle is listed in the list.

[0020] A list of vehicles is distributed to each vehicle in advance as support information, so that if a vehicle loses communication with an external server, it can immediately identify a vehicle from which to obtain the necessary support information using this list, without having to search for other vehicles to communicate with.

[0021] (3) The in-vehicle device may further include a reception possibility determination unit that determines whether or not assistance information can be received from an external server via a wireless communication device, and the assistance information transmission device may include a transfer device that transfers the driving assistance information received from the external server to the other in-vehicle device in response to receiving a request for distribution of assistance information from the other in-vehicle device when the determination by the list reference unit is positive and the determination by the reception possibility determination unit is positive.

[0022] Even if a vehicle is able to receive assistance information from an external server, another vehicle may request the delivery of driving assistance information from that vehicle. This indicates that some kind of failure has occurred that prevents that vehicle from communicating with the external server. Since the in-vehicle device according to this disclosure can receive assistance information by communicating with the external server, it can transfer the driving assistance information to other vehicles. As a result, even a vehicle that has experienced some kind of communication failure can immediately obtain driving assistance information.

[0023] (4) The in-vehicle device is In-vehicle device The transfer device may further include a buffer that stores the delivery requests received from the transfer device on a first-in, first-out basis, and may read the delivery requests from the buffer and ignore the delivery requests if the elapsed time from the reception time of the read delivery request to the current time is longer than a threshold time.

[0024] When a large number of distribution requests are concentrated, it may take some time to process them. When a certain amount of time has passed since receiving a distribution request, the vehicle may already have received driving assistance information from another vehicle. Therefore, in such a case, the distribution request can be ignored to reduce communication traffic and focus on real-time responses.

[0025] (5) The in-vehicle device may further include an internal server that constructs driving assistance information using information available to the in-vehicle device, and the assistance information transmission device may include a server initialization unit that initializes and starts the internal server in response to receiving a request for distribution of assistance information from an external device when the determination by the list reference unit is positive and the determination by the reception feasibility determination unit is negative, and a distribution unit that distributes the driving assistance information generated by the internal server to another in-vehicle device in response to receiving a request for distribution of assistance information from the other in-vehicle device.

[0026] If communication with the external server is possible and a vehicle equipped with the on-board device is on the list, the on-board device operates as an alternative server. The server initialization unit starts the internal server, and the internal server generates driving assistance information using information available to it. When a distribution request for assistance information is received from another vehicle, the distribution device can quickly distribute the generated driving assistance information. As a result, even if some kind of failure occurs in the external server, many vehicles can quickly obtain driving assistance information.

[0027] (6) The in-vehicle device is In-vehicle device The delivery device may further include a buffer that stores delivery requests received from the delivery device on a first-in, first-out basis, and the delivery device may read the delivery request from the buffer and ignore the delivery request if the elapsed time from the reception time of the read delivery request to the current time is longer than a threshold time.

[0028] When a large number of distribution requests are concentrated, it may take some time to process them. When a certain amount of time has passed since receiving a distribution request, the vehicle may already be receiving driving assistance information from another vehicle. Therefore, in such a case, the distribution request can be ignored to reduce communication traffic and focus on real-time responses.

[0029] (7) When the determination by the list inquiry unit is positive and the determination by the reception possibility determination unit is negative, the server initialization unit may initialize and start the internal server in response to receiving a number of delivery requests from outside within the most recent specified time period that exceeds a specified threshold.

[0030] When there are few distribution requests, it is not possible to determine whether a problem has occurred with the external server or whether only certain vehicles are unable to communicate with the external server. If the number of distribution requests received within a certain period of time exceeds a threshold, it can be determined that a problem has occurred with the external server. This prevents unnecessary processing by starting up the internal server even when it is not necessary.

[0031] (8) The server initialization unit may include a cooperative node candidate selection unit that selects multiple cooperative node candidates from multiple other vehicles that can communicate via wireless communication devices; a processing unit selection unit that selects a processing unit to realize the functions of the internal server; a dynamic state information acquisition unit that acquires information about the selected processing unit and dynamic states related to communication with the processing unit, and information about dynamic states related to communication with the outside; an initial information determination unit that selects at least one cooperative node based on the selected cooperative node candidate and the acquired dynamic states, and determines the type of sensor data to be collected from the cooperative node, the vehicles to which the driving assistance information will be distributed, and the distribution period for the driving assistance information; and a transfer unit that transfers the information determined by the initial information determination unit to a storage device of the internal server.

[0032] When the internal server is started, the server initialization unit sets the operating conditions of the internal server appropriately according to the situation at that time, so that the internal server can quickly generate the necessary driving assistance information based on the latest information and distribute it to each vehicle.

[0033] (9) The in-vehicle device may further include a timer that periodically operates the server initialization unit.

[0034] The server initialization unit operates periodically. The information used by the internal server for driving assistance information is updated each time. Because the internal server always generates and distributes driving assistance information based on the latest information, each vehicle can quickly access accurate driving assistance information.

[0035] (10) The vehicle-mounted device may further include a request transmission device that transmits a request for delivery of support information to at least one of the vehicles listed on the list when the determination by the list reference unit is negative and the determination by the reception feasibility determination unit is negative.

[0036] If the vehicle is not included in the list of vehicles that can act as an alternative server and communication with the server is interrupted, it will be necessary to obtain driving assistance information from an external vehicle. Since the list is distributed in advance, the driving assistance information can be obtained quickly by sending a distribution request to at least one vehicle on the list.

[0037] (11) The request transmitting device may transmit distribution requests in order from the top of the list until support information is returned.

[0038] Among the vehicles on the list, there may be cases where the internal server cannot be started for some reason, or it takes time to process a large number of distribution requests. In such cases, the driving assistance information cannot be obtained promptly. Therefore, by sending distribution requests to the vehicles on the list in order, the driving assistance information can be obtained as quickly as possible from vehicles that can distribute the driving assistance information.

[0039] (12) The request sending device may randomly rearrange the list before starting to send a distribution request.

[0040] By randomly sorting the list, it is possible to prevent distribution requests from concentrating on a few vehicles on the list, which results in the load being distributed among the vehicles on the list, allowing all vehicles to quickly obtain driving assistance information.

[0041] (13) The request transmitting device may randomly select a vehicle from the list and transmit a distribution request to it.

[0042] By randomly selecting vehicles from the list and sending distribution requests, it is possible to prevent distribution requests from concentrating on a few vehicles on the list. As a result, the load is distributed among the vehicles on the list, and all vehicles can quickly obtain driving assistance information.

[0043] (14) The vehicle-mounted device may further include an information transmission device that, in response to receiving an information distribution request from an external server requesting transmission of information regarding the static specifications and dynamic state of the vehicle-mounted device, transmits to the external server information regarding the static specifications or dynamic state of the vehicle-mounted device, as well as information regarding the static specifications or dynamic state of the computational resources or communication resources available to the vehicle-mounted device.

[0044] By doing so, when the external server creates a list of alternative server vehicles, it can select an appropriate vehicle and create and distribute an appropriate list. Examples of static specifications include the speed of wireless communication with the outside of the vehicle, the communication bandwidth of the in-vehicle network, and the processing capacity of the related ECU. Examples of dynamic conditions include the amount of data transmitted in wireless communication with the outside of the vehicle, the amount of data transmitted in the in-vehicle network, the load state of the ECU, and the number of surrounding vehicles with which communication is possible with a certain level of communication quality or higher. Either one of the static specifications or the dynamic conditions may be used, or both may be used. The same applies to computational resources and communication resources. The order of the alternative server vehicles in the list of alternative server vehicles is not particularly limited, and may be, for example, such that vehicles with higher scores determined by a combination of the static specifications and dynamic conditions described above are ranked higher.

[0045] (15) The vehicle-mounted device may further include a periodic operation determination unit that periodically determines whether the vehicle-mounted device should operate in place of the external server, and a notification device that notifies the external server of the result of the determination made by the periodic operation determination unit when the result is different from the previous determination.

[0046] Because the vehicle's status is constantly changing, the amount of computing resources available to the vehicle is also constantly changing. By receiving notification of these changes, the external server can appropriately update the list of vehicles that can act as alternative servers. The list distributed to vehicles receiving assistance information from the external server is also appropriately updated at the next distribution timing. As a result, even if each vehicle is unable to communicate with the external server, it can quickly obtain appropriate assistance information from a vehicle acting as an alternative server.

[0047] (16) A method for operating an in-vehicle device according to a second aspect of the present disclosure includes the steps of: a computer providing driving assistance to a vehicle using assistance information received from an external server via a wireless communication device; a computer determining whether or not the computer should operate in place of the external server in response to receiving a request for distribution of assistance information from another in-vehicle device; and a computer transmitting assistance information that can be used by the computer to the other in-vehicle device via the wireless communication device when the determination in the determination step is positive.

[0048] When the in-vehicle device is receiving assistance information from an external server and that communication is interrupted, the in-vehicle device determines whether or not it should take over from the external server. If the in-vehicle device determines that it should take over from the external server, it transmits assistance information that can be used by the in-vehicle device to other vehicles. Other vehicles that cannot communicate with the external server can provide driving assistance using the assistance information transmitted from this vehicle. As a result, even if a failure occurs in the external server, driving assistance can be immediately continued in many vehicles.

[0049] (17) A computer program according to a third aspect of the present disclosure causes a computer connected to a wireless communication device to function as a driving assistance device for providing driving assistance to a vehicle using assistance information received from an external server via the wireless communication device, an operation determination unit that determines whether the computer should operate in place of the external server in response to receiving a request for distribution of assistance information from another in-vehicle device, and an assistance information transmission device that transmits assistance information that the computer can use to the other in-vehicle device via the wireless communication device when the determination by the operation determination unit is positive.

[0050] When the in-vehicle device is receiving assistance information from the external server and the communication is interrupted, the operation determination unit determines whether the in-vehicle device should operate in place of the external server. . car The onboard equipment should operate The operation determination unitWhen the determination is made, the assistance information transmitting device transmits assistance information that can be used by the in-vehicle device to other vehicles. Other vehicles that cannot communicate with the external server can provide driving assistance using the assistance information transmitted from this vehicle. As a result, even if a failure occurs in the external server, driving assistance can be immediately continued in many vehicles.

[0051] (18) A driving assistance server according to a fourth aspect of the present disclosure is a driving assistance server that creates assistance information to assist driving within a management area and transmits it to vehicles within the management area, and includes: an assistance information creation unit that receives sensor data from a sensor that detects traffic conditions in the management area and creates the assistance information; an alternative server vehicle list creation unit that collects vehicle information regarding vehicles present within the management area and creates an alternative server vehicle list, which is a list of vehicles that can operate as alternative servers for the driving assistance server; and a transmission device that adds the alternative server vehicle list to the assistance information and transmits it to the vehicle.

[0052] If communication is interrupted while an in-vehicle device is receiving assistance information from a driving assistance server, each vehicle must search for a vehicle that can take over from the driving assistance server. However, if the driving assistance server creates a list of alternative server vehicles in advance and distributes this list together with the assistance information, each vehicle can quickly determine from which vehicle it should obtain assistance information. As a result, even if a failure occurs in the driving assistance server, assistance information can be immediately obtained by many vehicles.

[0053] (19) The alternative server vehicle list creation unit may include a divided area list creation unit that divides the management area into multiple divided areas and creates an alternative server vehicle list for each of the multiple divided areas, and the transmitting device may include an area-specific transmitting device that, for each of the multiple divided areas, attaches the alternative server vehicle list for that divided area to the support information and transmits it to each vehicle present in that divided area.

[0054] The area managed by the driving assistance server is divided into multiple partitions, an alternative server vehicle list is created for each partition, and the alternative server vehicle list for each partition is distributed. When communication with the driving assistance server is interrupted, each vehicle can use this alternative server vehicle list to immediately determine to which vehicle a distribution request should be sent to obtain assistance information. As a result, even if communication with the driving assistance server is interrupted, each vehicle can quickly obtain assistance information.

[0055] (20) A driving assistance method according to a fifth aspect of the present disclosure is a driving assistance method in a driving assistance system including a driving assistance server for creating assistance information to assist driving within a management area and transmitting it to vehicles within the management area, and includes the steps of a computer receiving sensor data from a sensor that detects traffic conditions in the management area and creating assistance information, a computer collecting vehicle information regarding vehicles present within the management area and creating an alternative server vehicle list that is a list of vehicles that can operate as alternative servers for the driving assistance server, and a computer adding the alternative server vehicle list to the assistance information and transmitting it to the vehicle.

[0056] If an on-board device is receiving assistance information from an external device and communication is interrupted, each vehicle must search for a vehicle that can distribute the assistance information. However, by creating a list of alternative server vehicles in advance and distributing the list together with the assistance information, each vehicle can quickly determine from which vehicle it should obtain assistance information. As a result, even if communication with the facility that distributes driving assistance information fails, each vehicle can immediately obtain the assistance information.

[0057] [Details of the embodiments of the present disclosure] Specific examples of an in-vehicle device, a method, a computer program, a driving assistance server, and a driving assistance method according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0058] 1. First embodiment 1 Configuration (1) Overall structure Referring to FIG. 1, a driving assistance system 50 according to the first embodiment includes an edge server 62 and a vehicle 60.

[0059] 1 , the vehicle 60 has various sensors such as a LiDAR 84, an on-board camera 82, and a millimeter-wave radar 80. The vehicle 60 also includes an on-board device 90 that collects sensor data from these sensors and transmits it to an edge server 62 via wireless communication, and receives information for driving assistance from the edge server 62 and uses the information for driving assistance. The information for driving assistance is, for example, a dynamic map. The vehicle 60 also includes various ECUs 92 that control various parts of the vehicle 60 under the control of the on-board device 90, and a cooperation control ECU 94 that cooperates with the on-board device 90 to execute processing when communication with the edge server 62 is interrupted or a request for distribution of a dynamic map is received from another vehicle.

[0060] The configuration of each part of the driving assistance system 50 will be described below.

[0061] (2) In-vehicle device 90 2 , the in-vehicle device 90 includes an exterior communication device 154 and an in-vehicle gateway 150 that controls communication between various sensors, various ECUs, etc. provided in the vehicle 60 and an in-vehicle / external linking unit 152 via a network (not shown) mounted on the vehicle 60. The in-vehicle device 90 further includes an interior / external linking unit 152 that receives driving assistance information such as a dynamic map from the edge server 62, sensor data from various sensors provided in the vehicle, and information on their operating states from the various ECUs. The in-vehicle device 90 further includes a driving assistance information storage unit 156 that stores various information including the driving assistance information received by the interior / external linking unit 152, and a selection unit 158 ​​that, under control of the linkage control ECU 94, selects and inputs to the in-vehicle / external linking unit 152 a dynamic map received by the exterior communication device 154 under normal circumstances and a dynamic map generated by the linkage control ECU 94 when communication with the edge server 62 is interrupted.

[0062] (3) Linkage control ECU94 A. Overall structure 2, the cooperation control ECU 94 mounted on the vehicle 60 includes, as its functional parts, a communication status detection unit 180 that monitors communication by the exterior communication device 154, detects the communication status with the edge server 62 and other vehicles, and extracts a distribution request for a dynamic map received from other vehicles. control The ECU 94 further includes a distribution request buffer 184 for temporarily storing the distribution requests extracted by the communication state detection unit 180 on a first-in, first-out basis. , connoisseur and a collaborative operation determination unit that determines an operation mode of collaborative operation by the in-vehicle device based on the communication state detected by the communication state detection unit and the number of distribution requests stored in the distribution request buffer.

[0063] The cooperation control ECU 94 further includes a mini edge server 188 for generating a map similar to the dynamic map received from the edge server 62 based on available information stored in the driving assistance information storage unit 156. The mini edge server 188 functions as an internal server of the vehicle 60. The cooperation control ECU 94 further includes a mini edge server initialization unit 190 for starting the mini edge server 188 in response to the cooperation operation determination unit 182 detecting a disruption of communication between the exterior communication device 154 and the edge server 62. At this time, the mini edge server initialization unit 190 extracts or generates information necessary for the dynamic map generated by the mini edge server 188 from the information stored in the driving assistance information storage unit 156 and stores the information in each storage unit within the mini edge server 188, thereby initializing the mini edge server 188 to operate appropriately. The cooperation control ECU 94 further includes a mini edge server output storage unit 192 for storing driving assistance information such as a dynamic map output from the activated mini edge server 188, and a transfer unit 186 for selecting appropriate data in accordance with the operation mode determined by the cooperation operation determination unit 182 and transmitting the selected data to the edge server 62 via the exterior communication device 154. The transfer unit 186 further responds to a distribution request stored in the distribution request buffer 184, reads out a dynamic map from the driving assistance information storage unit 156 or the mini edge server output storage unit 192 in accordance with the operation mode, and transmits the dynamic map to the sender of the distribution request via the exterior communication device 154, or inputs the map to the in-vehicle / exterior cooperation unit 152 via the selection unit 158.

[0064] The operation modes determined by the collaboration operation determination unit 182 include a normal mode, a transfer mode, and a distribution mode.

[0065] The normal mode is an operation mode when communication with the edge server 62 is normal and no distribution request is received.

[0066] The transfer mode is an operation mode when communication with the edge server 62 is normal and a distribution request is received from another vehicle.

[0067] The distribution mode is an operation mode when communication with the edge server 62 is interrupted and the number of distribution requests received from other vehicles exceeds a threshold within a predetermined time.

[0068] In the normal mode, the in-vehicle device 90 transmits the sensor data stored in the driving assistance information storage unit 156 to the edge server 62. Transporter 90 In the transfer mode, in addition to the operations in the normal mode, the mini edge server 188 transmits the dynamic map downloaded from the edge server 62 and stored in the driving support information storage unit 156 to the sender of the distribution request. The mini edge server 188 does not operate in the normal mode or the transfer mode. The mini edge server 188 operates only in the distribution mode.

[0069] B. Mini Edge Server 188 Referring to Figure 3, the mini edge server 188 includes a node memory unit 250 that stores other vehicles or infrastructure sensors that collect sensor data when creating a dynamic map, and vehicles, etc. to which the generated dynamic map is distributed (these vehicles and infrastructure sensors are referred to as "cooperative nodes").The mini edge server 188 also includes a sensor data collection unit 252 that collects sensor data from other vehicles via the exterior communication device 154 and from sensors in the vehicle itself via the in-vehicle device 90, based on the information on the cooperative nodes stored in the node memory unit 250.

[0070] The mini edge server 188 further includes a sensor data buffer 254 for temporarily storing the sensor data collected by the sensor data collection unit 252, and a sensor data analysis unit 256 for analyzing the sensor data stored in the sensor data buffer 254 and merging the results with a dynamic map received from the edge server 62 when communication with the edge server 62 was possible to create a new dynamic map.

[0071] C. Mini edge server initialization unit 190 4, the mini edge server initialization unit 190 includes a node information DB 302 that stores and manages information about nodes that can communicate with the vehicle 60, such as surrounding vehicles and infrastructure sensors, and a node information update unit 300 that updates the information stored in the node information DB 302 using information obtained from other nodes via communication and stored in the driving assistance information storage unit 156. The mini edge server initialization unit 190 further includes a vehicle resource DB 304 that stores specifications related to the computational resources, communication resources, sensors, etc. of the vehicle itself, and a timer 306 that periodically triggers initialization of the mini edge server 188 by the mini edge server initialization unit 190. The mini edge server initialization unit 190 further includes a node number determination unit 308 that determines the number of nodes to select as cooperative nodes by referring to the vehicle resource DB 304 in response to an initialization instruction from the timer 306. The mini edge server initialization unit 190 further includes a node determination unit 310 that, in response to a trigger by the timer 306 or an initialization instruction for the mini edge server 188 from the collaborative operation determination unit 182, selects nodes suitable as cooperative nodes from the node information DB 302, the number of which is determined by the node number determination unit 308, and stores them in the node memory unit 250 of the mini edge server 188.

[0072] The cooperative nodes selected by the node determination unit 310 include both data collection vehicles that collect sensor data and distribution vehicles that distribute the dynamic map generated by the mini edge server 188. The two sets may or may not be the same.

[0073] (4) Edge Server 62 5, edge server 62 includes a communication device 350 for communicating with the outside world via wired or wireless communication, and a receiving unit 352 for appropriately sorting data received by communication device 350 according to the content of the data. Edge server 62 further includes a dynamic map creating unit 362 for creating a dynamic map from the sensor data received by receiving unit 352 from each vehicle and infrastructure sensor and a high-resolution map stored in advance, and a dynamic map storage unit 364 for storing the dynamic map created by dynamic map creating unit 362.

[0074] The edge server 62 further includes a vehicle management unit 354 for receiving vehicle information from vehicles within the area managed by the edge server 62 via the receiving unit 352 and managing the vehicle information, and a vehicle information storage unit 356 which is a database for storing the vehicle information managed by the vehicle management unit 354. The edge server 62 further includes an alternative server vehicle list creation unit 358 for creating, based on the vehicle information stored in the vehicle information storage unit 356, an alternative server vehicle list that lists vehicles that can substitute for the edge server 62 in the event that communication between the vehicle and the edge server 62 is interrupted, and an alternative server vehicle list storage unit 360 for storing the alternative server vehicle list created by the alternative server vehicle list creation unit 358.

[0075] The edge server 62 further includes an alternative server vehicle list adding unit 366 that periodically reads out the dynamic map stored in the dynamic map storage unit 364 and adds the alternative server vehicle list stored in the alternative server vehicle list storage unit 360. The edge server 62 further includes a transmitting unit 368 that transmits the dynamic map with the alternative server vehicle list added as driving assistance information via the communication device 350 to a destination vehicle determined based on the vehicle information stored in the vehicle information storage unit 356.

[0076] (5) Program Structure A. Edge Server 62 The program that realizes the alternative server vehicle list creation unit 358 of the edge server 62 has the following control structure: In this embodiment, the alternative server vehicle list is created only for intersection areas where driving assistance is particularly required, but lists may also be created for other areas.

[0077] Referring to FIG. 6, this program includes step 400 of waiting until the update period of the alternative server vehicle list arrives, and step 402 of executing step 404 for all vehicles under management when the update period of the alternative server vehicle list arrives.

[0078] In step 404, the program sends an instruction to each vehicle requesting that it determine whether it is possible for each vehicle to act as an alternative server and send the result to the edge server 62.

[0079] The program further includes, following step 402, step 406 of receiving responses from each vehicle under its management, and step 408 of executing step 410 of creating an alternative server vehicle list for the intersection area managed by edge server 62.

[0080] Step 410 includes step 420 of determining an alternative server vehicle list consisting of vehicles present in the target intersection area that have the performance and dynamic resources to function as alternative servers based on the responses from each vehicle received in step 406, and step 422 of storing the alternative server vehicle list determined in step 420 in the alternative server vehicle list memory unit 360.

[0081] B. In-vehicle device 90 The program that realizes the in-vehicle device 90 has the following control structure. Referring to Fig. 7, this program includes step 450 of waiting until the update period of the dynamic map of the vehicle arrives, step 452 of confirming whether or not the dynamic map can be received from the edge server 62 in response to the arrival of the update period of the dynamic map, and step 454 of branching the control flow depending on whether or not the dynamic map has been received.

[0082] This program further includes step 456 for integrating the dynamic map received in step 452 with information held by the vehicle and utilizing the integrated information for driving assistance in response to a positive determination in step 454, and step 458 for determining whether the mini edge server 188 is operating and branching the control flow in accordance with the determination result. This program further includes step 460 for stopping the mini edge server 188 in response to a positive determination in step 458, and step 462 for setting the operation mode of the vehicle 60 to the normal mode and returning control to step 450 when the determination in step 458 is negative or after the determination in step 458 is positive and step 460 is completed. When the dynamic map is successfully received in step 452, the alternative server vehicle list added to the dynamic map is extracted and stored in a predetermined storage device.

[0083] This program further includes step 470, in response to a negative determination in step 454, for determining whether or not the host vehicle is included in the alternative server vehicle list held by the host vehicle and branching the control flow in accordance with the determination result, and step 472, in response to a negative determination in step 470, for transmitting a dynamic map distribution request to the alternative server vehicle at the top of the list (the vehicle with the highest priority as an alternative server). This program further includes step 474, in response to a negative determination in step 474, for determining whether or not the dynamic map has been received and branching the control flow in accordance with the determination result, step 476, in response to a negative determination in step 474, for branching the control flow in accordance with whether or not there is a vehicle that is included in the alternative server vehicle list with the next highest priority and to which a dynamic map distribution request has not yet been transmitted, and step 478, in response to a positive determination in step 476, for transmitting a dynamic map distribution request to that vehicle and returning control to step 474.

[0084] If the determination in step 474 is positive, it means that the dynamic map can be received, so control proceeds to step 456, where the information held by the vehicle is integrated with this dynamic map and used for driving assistance. The subsequent processing is the same as when the determination in step 454 is positive.

[0085] If the determination in step 476 is negative, it means that there are no more alternative server vehicles, so control proceeds to step 480, where the vehicle operates based only on the information held by the host vehicle. Control then returns to step 450. In such a case, it is desirable to inform the driver that driving assistance information cannot be acquired.

[0086] 8, this program further includes step 500 for branching the control flow depending on whether the mini edge server 188 is operating in the host vehicle in response to a positive determination in step 470, and step 502 for branching the control flow depending on whether the number of dynamic map distribution requests received from other vehicles within a predetermined time period exceeds a predetermined threshold in response to a negative determination in step 500. This program further includes step 504 for performing initialization to operate the mini edge server 188 in response to a positive determination in step 502, and step 506 for starting the mini edge server 188 after the processing of step 504 is completed and returning control to step 450 in FIG.

[0087] If the determination in step 500 is positive, or if the determination in step 502 is negative, control returns to step 450 in FIG. 7 without executing steps 504 and 506.

[0088] C. Mini edge server initialization unit 190 Step 504 in Fig. 8 corresponds to the processing performed by the mini edge server initialization unit 190 in Fig. 4. Referring to Fig. 9, the program realizing the mini edge server initialization unit 190 includes step 550 of observing the connection quality with surrounding vehicles. Indicators for measuring the connection quality here include whether communication is possible in the first place, the throughput when communication is possible, the communication delay time, etc.

[0089] After step 550, this program further includes step 552, in which a predetermined number of cooperative node candidates are determined by selecting vehicles with high static specifications (so-called specs) from among the surrounding vehicles. This program further includes step 554, in which ECUs in the host vehicle that actually generate and transfer data for constructing a dynamic map are extracted based on the specifications of the ECUs, and step 556, in which information on the current dynamic state of the ECUs extracted in step 554 is acquired. This program further includes step 558, in which, from the vehicles selected in step 552, a data collection vehicle, a type of collected data, a dynamic map distribution vehicle, and a distribution cycle are determined based on the amount of information that the host vehicle can process. The determination in step 558 is made based on the dynamic state acquired in step 556. This program further includes step 560, in which the determined information is transferred to the mini edge server 188 and the process is terminated. The dynamic state information collected here includes the operating load of the ECU's CPU (Central Processing Unit), memory usage, communication delay, etc.

[0090] D. Delivery request reception processing In vehicle 60, communication status detection unit 180 shown in Fig. 2 runs the process described below when it receives a distribution (transfer) request from another vehicle, in addition to the processes described above. Referring to Fig. 10, this distribution request reception program includes step 600 of writing the received distribution request to distribution request buffer 184 shown in Fig. 2, and step 602 of branching the control flow depending on whether the number of distribution requests received within a predetermined period of time most recently exceeds a predetermined threshold. This program further includes step 604 of setting the operation mode to distribution mode and terminating execution of this program in response to a positive determination in step 602, and step 606 of setting the operation mode to transfer mode and terminating execution of this program in response to a negative determination in step 602.

[0091] If the vehicle is not listed in the alternative server vehicle list, such a distribution request will not be received. Therefore, in that case, this program will not be started. Alternatively, after the program is started, a step may be provided before step 600 to determine whether the vehicle is listed in the alternative server vehicle list, and if the determination is negative, execution of this program may be immediately terminated.

[0092] E. Distribution processing When the delivery mode is entered in step 604 in Fig. 10, and when the transfer mode is entered in step 606, the following delivery program is executed by transfer unit 186 shown in Fig. 2. Referring to Fig. 11, this program includes step 650 of waiting until a delivery request is stored in delivery request buffer 184, and step 652 of reading the delivery request from delivery request buffer 184 in response to determining in step 650 that the delivery request is stored in delivery request buffer 184. This program further includes, following step 652, step 654 of branching the flow of control depending on whether the elapsed time from the time the delivery request was received to the time the delivery request was read (the current time) is within a predetermined threshold time.

[0093] This program further includes step 656 for branching the control flow depending on whether the mini edge server 188 is operating or not, in response to the affirmative determination in step 654, and step 658 for reading the dynamic map created by the mini edge server 188 from the mini edge server output storage unit 192 of Fig. 2, distributing it to the vehicle that transmitted the distribution request, and returning control to step 650, in response to the affirmative determination in step 656. This program further includes step 660 for transferring the dynamic map stored in the driving assistance information storage unit 156 to the sender of the distribution request, and returning control to step 650, in response to the negative determination in step 656. The dynamic map is received by the exterior communication device 154 from the edge server 62 and stored in the driving assistance information storage unit 156 via the interior / exterior cooperation unit 152.

[0094] In this example, in the distribution mode, the transfer unit 186, apart from this process, periodically transfers the dynamic map stored in the mini edge server output storage unit 192 to the in-vehicle / out-of-vehicle linkage unit 152 via the selection unit 158. The in-vehicle / out-of-vehicle linkage unit 152 operates based on this dynamic map in the same way as in the normal mode to provide driving assistance.

[0095] Mini Edge Server 188 The program that realizes the mini edge server 188 has the following control structure: Referring to Fig. 12, this program includes step 700 of collecting sensor data from sensors of the vehicle and surrounding vehicles determined to be data collection vehicles, step 702 of analyzing the sensor data collected in step 700 and constructing a dynamic map, and step 704 of saving the dynamic map constructed in step 702 in the mini edge server output storage unit 192 shown in Fig. 2 and returning control to step 700.

[0096] The mini edge server 188 periodically executes this program when it is running. To terminate the processing of the mini edge server 188, it directly instructs the arithmetic processing unit to terminate the execution of the program.

[0097] G Status update processing An alternative server vehicle is selected primarily based on the vehicle's specifications and the dynamic state of the on-board device's hardware at the time of selection. Specifications are static information, but the dynamic state is literally constantly changing. Therefore, even if a vehicle has sufficient performance and dynamic state margins to be an alternative server vehicle at the time of selection, its dynamic state may change due to changes in traffic conditions or the execution of some processing in the vehicle. These changes may cause the vehicle to no longer be able to meet the condition of having sufficient performance and dynamic state to be an alternative server vehicle.

[0098] In this embodiment, in such a case, the vehicle notifies the edge server 62 of the change in the vehicle state. A program for this purpose runs periodically in the cooperation control ECU 94.

[0099] 13, this program includes step 750, which waits until the execution period of the determination process arrives or until some state change is detected in the on-board device and each on-board ECU, etc. The program further includes step 752, which collects information about the host vehicle, i.e., its dynamic state, in response to the end of the wait in step 750, and step 754, which branches the control flow depending on whether the host vehicle satisfies the conditions to be an alternative server vehicle based on the information about the dynamic state collected in step 752. The program further includes step 756, which switches the vehicle's operating mode to a low-load operating mode in response to a negative determination in step 754, and step 758, which notifies the edge server 62 of the new operating mode and returns control to step 750. If the determination in step 754 is positive, control immediately returns to step 750.

[0100] 2 operations Each part of the driving assistance system 50 having the above-described configuration operates as follows.

[0101] (1) Edge Server 62 figure 5, the edge server 62 performs a process in which the communication device 350 communicates with the outside and appropriately distributes the data received by the communication device 350 according to the content of the data. Sensor The data is provided to the dynamic map creation unit 362, and the vehicle information from each vehicle within the management area is provided to the vehicle management unit 354.

[0102] The dynamic map creating unit 362 analyzes the received data to create a dynamic map at regular intervals and stores it in the dynamic map storage unit 364. As a result, the dynamic map is updated to the latest map at regular intervals.

[0103] The vehicle management unit 354 updates the vehicle database that constitutes the vehicle information storage unit 356 based on vehicle information from vehicles in the area managed by the edge server 62. As a result, the vehicle information stored in the vehicle information storage unit 356 is updated to the latest information at regular intervals.

[0104] The alternative server vehicle list creation unit 358 periodically creates an alternative server vehicle list based on the vehicle information stored in the vehicle information storage unit 356. This creation uses the specifications and dynamic status of each vehicle. Note that when the vehicle's operating mode is changed due to the dynamic status, the vehicle information in the vehicle information storage unit 356 is updated and taken into consideration when creating the alternative server vehicle list. The alternative server vehicle list storage unit 360 stores the alternative server vehicle list created by the alternative server vehicle list creation unit 358.

[0105] 6, in this process, an instruction to determine whether an alternative server vehicle is available is first sent to each vehicle in the area managed by the edge server 62 (step 402), and a response is received (step 406). Based on the data obtained as a result, an alternative server vehicle list for each intersection area is determined in step 408 (step 420), and stored in the alternative server vehicle list storage unit 360 shown in FIG. 5 (step 422).

[0106] Referring again to FIG. 5, the alternative server vehicle list adding unit 366 periodically reads out the dynamic map stored in the dynamic map storage unit 364, and adds the alternative server vehicle list stored in the alternative server vehicle list storage unit 360. list The transmission unit 368 periodically transmits the dynamic map to which the alternative server vehicle list has been added by the alternative server vehicle list adding unit 366 to a destination vehicle determined based on the vehicle information stored in the vehicle information storage unit 356 via the communication device 350.

[0107] (2) 60 vehicles The vehicle 60 operates as follows.

[0108] A. Normal mode 2, in the normal mode, the cooperative operation determination unit 182 of the in-vehicle device 90 controls the selection unit 158 ​​so that the in-vehicle / out-of-vehicle cooperation unit 152 receives data from the exterior communication device 154, and the data from the in-vehicle / out-of-vehicle cooperation unit 152 is transmitted to the edge server 62 via the exterior communication device 154. The mini edge server 188 does not operate.

[0109] More specifically, referring to Fig. 7, when the update period for the dynamic map arrives in step 450, the dynamic map is received from the edge server 62 in step 452. Normally, reception of the dynamic map is successful. Therefore, the determination in step 454 is positive, and in step 456, information held by the vehicle itself is integrated with the received dynamic map and used for driving assistance. The determination in step 458 is negative, and control returns to step 450. At this time, the alternative server vehicle list added to the dynamic map is separated and saved in a predetermined storage device.

[0110] In parallel with this, the vehicle interior / exterior linking unit 152 receives information from each sensor mounted on the vehicle via the vehicle gateway 150 and periodically transmits it to the edge server 62 via the exterior communication device 154 .

[0111] B. Transfer mode The condition for entering the transfer mode is that a dynamic map distribution request is received from another vehicle in normal mode. When a distribution request is received, the communication status detection unit 180 shown in FIG. 2 detects it and stores the distribution request in the distribution request buffer 184. As a result, the vehicle 60 enters the transfer mode. The following explanation will cover two cases: when the vehicle 60 is listed in the alternative server vehicle list, and when it is not.

[0112] (A) If vehicle 60 is not listed in the alternative server vehicle list In this case, distribution requests from other vehicles should not normally arrive at vehicle 60. Therefore, as described in the explanation of FIG.

[0113] Conversely, in this case, if only vehicle 60 cannot communicate with edge server 62, the data will be transferred from an appropriate vehicle by referring to the alternative server vehicle list that has already been received, via the route of steps 452, 454, 470, and 472 shown in Figure 7.

[0114] (a) If vehicle 60 is listed in the alternative server vehicle list In this case, there is a possibility that a distribution request from another vehicle will arrive at vehicle 60. However, even in this case, there are two possibilities. The first is that edge server 62 is operating normally, but some vehicles are unable to communicate with edge server 62 for some reason. The second is that edge server 62 itself has malfunctioned. These will be explained in order below.

[0115] A. Case 1 In the first case, it can be assumed that the majority of vehicles, including vehicle 60, can communicate normally with edge server 62. Therefore, distribution requests will only come from a very limited number of vehicles. In such a case, the number of distribution requests received by vehicle 60 within a given time period should be very small. Therefore, the determination in step 602 shown in FIG. 10 is negative, and vehicle 60 enters forwarding mode.

[0116] At this time, the process shown in FIG. 7 is executed in the same manner as in the normal mode.

[0117] 11, which is executed periodically, the processes of step 650, step 652, and step 654 are executed. Assuming that the determination in step 654 is positive, the determination in step 656 is negative (i.e., it is determined that the operation mode is the transfer mode), and the dynamic map that has already been received from the edge server 62 and stored in the driving assistance information storage unit 156 in FIG. 2 is read out from the driving assistance information storage unit 156 and transferred to the vehicle that has sent the distribution request.

[0118] B. Second Case In the second case, none of the surrounding vehicles can communicate with the edge server 62. Therefore, the processes of steps 472 to 478 in Fig. 7 are executed in each vehicle, and a distribution request is sent to the vehicle 60. In other words, in this case, the number of distribution requests that the vehicle 60 receives within a certain period of time should be large.

[0119] First, in this case, the process goes through step 452, step 454, and step 470 in Fig. 7, and then step 500 shown in Fig. 8 is executed. Since the mini edge server 188 has not been started immediately after the communication interruption, the determination in step 500 is negative, and step 502 is executed. Under the conditions assumed here, the determination in step 502 is positive, and steps 504 and 506 are executed, and the mini edge server 188 is started.

[0120] In this case, the process of Fig. 10 is executed in parallel. This process is executed for multiple delivery requests, and all delivery requests are accumulated in delivery request buffer 184. At some point, the determination in step 602 becomes positive, and the process of step 604 is executed, and the operation mode of vehicle 60 is set to the delivery mode.

[0121] 11 is also executed in parallel. Normally, the determination in step 650 is negative, so the distribution process is not executed. However, if the edge server 62 fails, dynamic map distribution requests to the vehicle 60 will be concentrated. Therefore, the determination in step 650 will be positive.

[0122] The transfer unit 186 sequentially reads out the distribution requests from the distribution request buffer 184, and if the condition of step 654 is met, steps 656 to 658 are executed, and the dynamic map generated by the mini edge server 188 is distributed to the sender of the distribution request. This process is repeated. Delivery request buffer 184 The distribution requests stored in the queue are processed in order.

[0123] If a certain amount of time has passed since the delivery request arrived, the dynamic map generated by the mini edge server 188 may no longer be appropriate. Step 654 is provided to deal with this problem.

[0124] When the edge server 62 returns to a normal state and communication between the vehicle 60 and other vehicles and the edge server 62 is resumed, the process of steps 452, 454, 456, 458, and 460 in Fig. 7 is executed to shut down the mini edge server 188. In the following step 462, the operating mode is changed to the normal mode, and the vehicle 60 returns to normal operation.

[0125] 3. Effects As described above, according to this embodiment, the edge server 62 creates an alternative server vehicle list in advance and distributes it to each vehicle along with a dynamic map. When communication between a vehicle and the edge server 62 is interrupted, the vehicle transmits a dynamic map distribution request to a vehicle determined from the alternative server vehicle list. Therefore, each vehicle can obtain a dynamic map more quickly than if the search for an alternative server was initiated after communication was interrupted. Furthermore, even when communication with each vehicle is interrupted due to a failure in the edge server 62, a vehicle listed on the alternative server vehicle list can quickly begin operating as an alternative server based on the arrival status of the distribution request. This reduces the time required to determine an alternative server, thereby minimizing the impact of a failure in the edge server 62. Furthermore, even if the edge server 62 is functioning normally, if a vehicle cannot communicate with the edge server 62 for some reason, the dynamic map can be quickly obtained by requesting distribution of a dynamic map from a vehicle listed on the alternative server vehicle list. When the number of such vehicles is limited, there is no need to launch an alternative server (mini server), and the necessary information can be provided to the vehicle with minimal processing.

[0126] Second Embodiment 1 Configuration (1) Management area In the first embodiment, an alternative server vehicle list is created and distributed for each intersection area managed by the edge server 62. All vehicles in the same area use the same alternative server vehicle list, while vehicles in different areas use different alternative server vehicle lists.

[0127] However, the number of vehicles present within an intersection often varies depending on the intersection area. In particular, processing efficiency may differ between intersections with a large number of vehicles and those with a small number of vehicles. In other words, at intersections with a large number of vehicles, if an alternative server were to be operated, the load on the vehicles would be too great, making it difficult to quickly distribute dynamic maps to all vehicles. Conversely, at intersections with a small number of vehicles, situations often arise where the processing capacity of the vehicle functioning as an alternative server is not fully utilized.

[0128] As a result, a situation may arise in which the overall resources of the vehicle managed by the edge server cannot be used appropriately and efficiently.

[0129] Therefore, in the second embodiment, the intersection area is divided or multiple intersection areas are combined depending on the number of vehicles present in each intersection area.

[0130] (2) Division and integration of management areas 14 schematically shows a management area 800 managed by an edge server 810 according to the second embodiment. The management area 800 is divided into areas 820, 822, and 824. Area 820 is adjacent to an intersection 830. Area 822 includes the intersection 830. Area 824 includes both the intersection 832 and the intersection 834.

[0131] Management area 800 was originally divided into an area including intersection 830 (areas 820 and 822), an area including only intersection 832, and an area including only intersection 834. However, management area 800 is divided as shown in FIG. 14 because, while a large number of vehicles exist at intersection 830 and its surrounding area, there are not many vehicles at either intersection 832 or intersection 834. Furthermore, the area including intersection 830 is divided into areas 820 and 822 because there are many vehicles, but it is divided into areas 820 and 822 in order to divide the number of vehicles as equally as possible. Such division and integration of areas is performed dynamically according to the number of vehicles present near each intersection.

[0132] In order to combine or divide regions in this way, it is convenient to use so-called graph theory. Referring to Figure 15, when the regions including intersection 830, intersection 832, and intersection 834 in Figure 14 are provided separately, the relationship between these regions is represented by graph 850.

[0133] Graph 850 includes node 860 corresponding to the region including intersection 830, node 862 corresponding to the region including intersection 832, and node 864 corresponding to the region including intersection 834. The fact that intersection 830 and intersection 832 are connected by a road, and the fact that intersection 832 and intersection 834 are also connected by a road, are represented by an edge connecting node 860 and node 862 and an edge connecting node 862 and node 864. If there is no edge between two nodes, those two nodes cannot be directly merged. For example, there is no edge between node 860 and node 864. This indicates that the region including intersection 830 and the region including intersection 834 cannot be merged without including the region including intersection 832.

[0134] Each node has, as node information, a node identifier (node ​​ID), coordinates defining the area corresponding to the node, its area, and the number of vehicles present in the area.

[0135] When the divided area is represented as a graph, it is easy to determine that, for example, if the number of vehicles at node 860 is greater than a threshold, the area should be divided into two or more parts. Such processing corresponds to dividing node 860 into two nodes, node 880 and node 882, which are connected to each other by a new edge. Furthermore, if the total number of vehicles at two adjacent nodes is equal to or less than a threshold, these two nodes can be merged to form new node 884. In this case, all edges other than those connecting node 862 and node 864 can be carried over to node 884. In this way, a new graph 870 is obtained.

[0136] (3) Edge Server Figure 16 shows the configuration of an edge server 810 according to the second embodiment. The edge server 810 shown in Figure 16 differs from the edge server 62 according to the first embodiment shown in Figure 5 in that it further includes an area management unit 900 that manages the management areas of the edge server 810 so as to divide and combine them using the method described above, and that it includes an alternative server vehicle list creation unit 902 that creates a separate alternative server vehicle list for each divided area to be divided and combined, instead of the alternative server vehicle list creation unit 358 shown in Figure 5. In all other respects, the edge server 810 has the same configuration as the edge server 62.

[0137] (4) Program Structure 17 shows the control structure of a program that realizes the functions of the above-described area management unit 900. Referring to FIG. 17, this program includes step 920 of creating an initial graph in accordance with initial information prepared in advance, and step 922 of updating each node information of the graph created in step 920 by collecting information from the corresponding area. The program further includes step 924 of executing step 926, described below, for each edge of the graph whose node information has been updated in step 922, step 928 of executing step 930, described below, for each node after step 924, and step 932 of creating an alternative server vehicle list for each node after completion of the processing of step 928, and returning control to step 922.

[0138] Step 926 includes step 940, which branches the control flow depending on whether the number of vehicles at either of the end nodes of the target edge is smaller than a threshold, and step 942, which branches the control flow depending on whether the areas of the end nodes are within a range where communication is possible between the vehicles present therein, in response to a positive determination in step 940. Step 926 further includes step 944, which, in response to a positive determination in step 942, deletes the target edge, merges the end nodes, and terminates step 926. If the determination in step 940 is negative, or if the determination in step 942 is negative, the nodes are not merged and step 926 terminates.

[0139] Step 930 includes step 950, which determines whether the number of vehicles in the target node exceeds a threshold and branches the flow of control according to the determination, and step 952, which, if the determination in step 950 is positive, divides the node so that the number of vehicles is approximately equal, creates a new edge between the nodes, and ends step 930. If the determination in step 950 is negative, step 930 ends without dividing the node.

[0140] 2 operations As is clear from the above description and the description of FIG. 17 , in the second embodiment, a divided area within an area managed by the edge server 810 is dynamically divided into two further divided areas, or two divided areas are dynamically merged. By repeating this process, multiple divided areas are dynamically merged into one divided area, or one divided area is divided into multiple divided areas. The dynamic map distribution process and the process of creating an alternative server vehicle list for each divided area, which are performed by the edge server 810, are the same as those in the first embodiment; only the target divided area changes dynamically.

[0141] 3. Effects As described above, according to the second embodiment, the number of vehicles in each divided area can be equalized. Even if the edge server 810 cannot distribute dynamic maps for some reason, the alternative server vehicle list has been distributed in advance, so distribution of dynamic maps by alternative server vehicles in each divided area can be quickly started. In addition, it is possible to prevent a situation in which an excessive load is placed on some alternative server vehicles.

[0142] 3. Hardware Configuration The edge server 62 of the first embodiment and the edge server 810 of the second embodiment can be realized by ordinary computer hardware, except that a communication function is essential. Also, for example, the in-vehicle device 90 and the cooperative control ECU 94 of the vehicle 60 can be realized by an information processing device centered on a processor, which is normally used.

[0143] 18 shows a hardware block diagram of a computer for implementing, for example, the edge server 62. The edge server 810 has a similar configuration.

[0144] FIG. 18 is a hardware block diagram of a computer system that realizes each of the above embodiments.

[0145] 18, the edge server 62 includes a computer 970 having a DVD (Digital Versatile Disc) drive 1002, and a keyboard 974, a mouse 976, and a monitor 972 for interacting with a user, all of which are connected to the computer 970. Of course, these are just one example of a configuration for when user interaction is required, and any general hardware and software that can be used for user interaction (e.g., a touch panel, voice input, or a general pointing device) can be used.

[0146] The computer 970 includes a DVD drive 1002, a CPU 990, a graphics processing unit (GPU) 992, and a bus 1010 connected to the CPU 990, the GPU 992, and the DVD drive 1002. The computer 970 further includes a read-only memory (ROM) 996 connected to the bus 1010 and storing a boot-up program and the like for the computer 970, and a random access memory (RAM) 998 connected to the bus 1010 and storing instructions constituting the program, a system program, working data, and the like. The computer 970 further includes a solid state drive (SSD) 1000, which is nonvolatile memory connected to the bus 1010. The SSD 1000 is used to store programs executed by the CPU 990 and the GPU 992, as well as data used by the programs executed by the CPU 990 and the GPU 992. The computer 970 further includes a network I / F (Interface) 1008 that provides connection to a network 986 that enables communication with in-vehicle devices and various infrastructure sensors, and a USB port 1006 to which a USB (Universal Serial Bus) memory 984 can be attached or detached and that provides communication between the USB memory 984 and various parts within the computer 970.

[0147] The computer 970 further includes an audio I / F 1004 connected to the microphone 982, the speaker 980, and the bus 1010. The audio I / F 1004 has the function of reading out audio signals, video signals, and text data generated by the CPU 990 and stored in the RAM 998 or the SSD 1000 in accordance with instructions from the CPU 990, converting them to analog, amplifying them, and driving the speaker 980, and digitizing the analog audio signal from the microphone 982 and storing it in the RAM 998 or the SSD 1000 at any address specified by the CPU 990.

[0148] In the above embodiment, the computer programs and the like that realize the functions of the edge server 62 and the edge server 810 are all stored in, for example, the SSD 1000, RAM 998, DVD 978, or USB memory 984 shown in Fig. 18 , or a storage medium of an external device (not shown) connected via the network I / F 1008 and the network 986. Typically, these data, parameters, and the like are written to the SSD 1000 from the outside, for example, and loaded into the RAM 998 when the computer 970 is executed.

[0149] Computer programs for operating this computer system to realize the functions of edge server 62, edge server 810, and each of their components are stored on a DVD 978 inserted into a DVD drive 1002 and transferred from the DVD drive 1002 to the SSD 1000. Alternatively, these programs may be stored on a USB memory 984, which may be inserted into a USB port 1006 and the programs transferred to the SSD 1000. Alternatively, the programs may be transmitted to the computer 970 via a network 986 and stored in the SSD 1000.

[0150] The program is loaded into RAM 998 when executed. Of course, a source program may be input using the keyboard 974, monitor 972, and mouse 976, and the compiled object program may be stored in SSD 1000. In the case of a scripting language, a script input using the keyboard 974 or the like may be stored in SSD 1000. In the case of a program that runs on a virtual machine, a program that functions as a virtual machine must be installed in advance on computer 970. Because server processing involves a large amount of calculation, it is preferable to realize each part of the embodiments of the present disclosure as an object program consisting of native computer code rather than a scripting language.

[0151] The CPU 990 reads a program from the RAM 998 according to an address indicated by an internal register called a program counter (not shown) and interprets the instructions. The CPU 990 further reads data required to execute the instructions from the RAM 998, the SSD 1000, or other devices according to the address specified by the instruction, and executes the processing specified by the instruction. The CPU 990 stores the execution result data at an address specified by the program, such as the RAM 998, the SSD 1000, or a register within the CPU 990. At this time, the value of the program counter is also updated by the program. The computer program may be loaded directly into the RAM 998 from the DVD 978, the USB memory 984, or via a network. Note that some tasks (mainly numerical calculations) of the program executed by the CPU 990 are dispatched to the GPU 992 according to instructions included in the program or according to the analysis results obtained when the CPU 990 executes the instructions.

[0152] The program that enables the computer 970 to implement the functions of each unit according to the above-described embodiments includes a plurality of instructions written and arranged to cause the computer 970 to operate to implement those functions. Some of the basic functions required to execute these instructions are provided by the operating system (OS) or third-party programs running on the computer 970, or by modules of various toolkits installed on the computer 970. Therefore, the program does not necessarily include all of the functions required to implement the system and method of this embodiment. The program need only include instructions that execute the operations of the above-described devices and their components by statically linking appropriate functions or "programming toolkit" functions in a controlled manner to achieve the desired results, or by dynamically calling them during program execution. The method for operating the computer 970 in this manner is well known, and will not be repeated here.

[0153] The GPU 992 is capable of parallel processing, and can execute a large amount of calculations involved in server processing simultaneously in parallel or in a pipelined manner. For example, parallel calculation elements discovered in a program when the program is compiled or when the program is executed are dispatched from the CPU 990 to the GPU 992 as needed, and executed. The results are returned to the CPU 990 directly or via a specified address in the RAM 998, and assigned to a specified variable in the program.

[0154] 19 exemplarily illustrates the sensor arrangement and network configuration of a vehicle 60. Referring to Fig. 19, the vehicle 60 includes a network 1200 having a gigabit-class transmission speed to which the above-described in-vehicle device 90 and the cooperative control ECU 94 are connected, and a sensor unit 1280, a sensor unit 1282, a sensor unit 1284, and a sensor unit 1286 mounted on the right front, left front, right rear, and left rear of the vehicle 60, respectively.

[0155] Each of the sensor unit 1280, the sensor unit 1282, the sensor unit 1284, and the sensor unit 1286 includes a millimeter wave radar, a camera, and a LiDAR.

[0156] In this embodiment, the in-vehicle network 1200 includes four gigabit-class network switches 1292, 1294, 1296, and 1298, each connected to sensors belonging to the same sensor unit. The in-vehicle network 1200 further includes a first multi-gigabit switch 1300 that bridges the two network switches 1292 and 1294 at the front of the vehicle, and a second multi-gigabit switch 1302 that bridges the two network switches 1296 and 1298 at the rear of the vehicle and is connected to the first multi-gigabit switch 1300. The in-vehicle device 90 is connected to the network switch 1292, and the cooperation control ECU 94 is connected to the network switch 1294. A TCU (Telematics Control Unit) 1290, which corresponds to the exterior communication device 154 shown in FIG. 2, is connected to the network switch 1292 together with the in-vehicle device 90.

[0157] As described above, sensor unit 1280, sensor unit 1282, sensor unit 1284, and sensor unit 1286 are located in different positions on the vehicle. Therefore, the value of the sensor data from these sensor units may differ depending on the vehicle's circumstances, as will be described later. Furthermore, the amount of data from various sensors, particularly from cameras, is large. Although not shown in FIG. 19, the vehicle is equipped with multiple ECUs, as will be described later with reference to FIG. 20. These ECUs all communicate with the in-vehicle device 90 via the network 1200. Therefore, communication via the network 1200 can sometimes experience delays. This delay must be taken into consideration when vehicle 60 functions as an alternative server vehicle.

[0158] FIG. 20 is a block diagram showing a schematic hardware configuration of an in-vehicle device 90. Referring to FIG. 20, the in-vehicle device 90 includes an HMI (Human-Machine Interface) controller 1332 connected to an in-vehicle Local Area Network (LAN) and an exterior communication controller 1330 connected to the in-vehicle LAN, similar to the HMI controller 1332. The in-vehicle device 90 further includes an integrated antenna 1340 connected to the exterior communication controller 1330 and functioning as an antenna for a fifth-generation mobile communication system (so-called "5G"), an intelligent transport system (so-called "ITS (Intelligent Transport Systems)"), a global positioning system (GPS), and Wi-Fi. GPS is a type of global navigation satellite system (GNSS). The in-vehicle device 90 further includes an automatic driving controller 1334 connected to the HMI controller 1332 and the exterior communication controller 1330 via the in-vehicle LAN, and a driving system controller 1336 connected to the in-vehicle LAN.

[0159] The HMI controller 1332 is connected to a monitor 1342 and a plurality of ECUs 1344 and 1346 .

[0160] The autonomous driving controller 1334 is connected to a millimeter wave radar 1312, an in-vehicle camera 1314, a LiDAR 1316, and an autonomous driving ECU 1348.

[0161] The driving system controller 1336 is connected to an ECU 1350, an ECU 1352, an ECU 1354, an ECU 1356, and the like for controlling the driving of the vehicle.

[0162] These ECUs and the on-board device 90 are essentially computers, each of which includes a processor and dedicated memory (not shown). These processors and memories are also capable of sharing various processes for making the vehicle 60 function as an alternative server vehicle in cooperation with the on-board device 90 under control of the on-board device 90. Therefore, the operating status of these processors and the usage status of the memory should also be taken into consideration when determining whether the vehicle 60 can function as an alternative server vehicle.

[0163] Fourth Variation In the above embodiment, the mini edge server 188 is activated only in the distribution mode and is deactivated when the distribution mode ends. However, this disclosure is not limited to such an embodiment. For example, the mini edge server 188 may be activated at all times so that it can immediately take over from the edge server when the distribution mode is entered. Alternatively, the mini edge server 188 may be activated only in the distribution mode, but the mini edge server initialization unit 190 may be operated periodically. In this case, the initialization work at the time of startup of the mini edge server 188 can be omitted, and the time until it can function as a substitute server vehicle to replace the edge server can be shortened.

[0164] In the above embodiment, the alternative server vehicle list includes only those servers that can operate as distribution servers. However, this disclosure is not limited to such an embodiment. It may also include not only those servers that can perform distribution but also those servers that can only operate as transfer servers. Alternatively, the alternative server vehicle list may be created with a list of distribution servers and a list of transfer servers, and both may be transferred. In this case, a vehicle that loses communication with the edge server may first select a vehicle from the list of transfer servers and request the transfer of a dynamic map. If the transfer is not successful, the vehicle may access the distribution server. This prevents requests from concentrating on alternative server vehicles when a transfer would suffice.

[0165] In the above embodiment, a vehicle that has lost communication with the edge server transmits a distribution request in order from the top of the alternative server vehicle list. However, this disclosure is not limited to such an embodiment. For example, the order in which vehicles listed in the alternative server vehicle list are selected may be randomized. This prevents distribution requests from concentrating on the vehicle listed at the top of the alternative server vehicle list. To achieve the same effect, the alternative server vehicle list may be randomly rearranged before selecting a vehicle. Alternatively, when transmitting the alternative server vehicle list from the edge server to each vehicle, the alternative server vehicle list may be reorganized so that the order differs for each vehicle.

[0166] In the above embodiment, it is assumed that a dynamic map is transmitted as a driving assistance service. However, this disclosure is not limited to such an embodiment. This disclosure can also be applied to a driving assistance service that transmits traffic information, road conditions, weather, event information, and the like to a vehicle in addition to a dynamic map. In other words, driving assistance information is not limited to a dynamic map, but includes any information for assisting driving.

[0167] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is not defined by the detailed description of the disclosure, but by the claims of the appended claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0168] 50 Driving assistance system 60 vehicles 62, 810 Edge Server 80, 1312 Millimeter wave radar 82, 1314 In-vehicle camera 84, 1316 LiDAR 90 On-vehicle equipment 92 Various ECUs 94 Linkage Control ECU 150 In-vehicle gateway 152 In-vehicle and out-of-vehicle coordination department 154 External communication device 156 Driving assistance information storage unit 158 Selection Section 180 Communication status detection unit 182 Collaborative Action Decision Unit 184 Delivery Request Buffer 186 Transfer Department 188 Mini Edge Server 190 Mini Edge Server Initialization Unit 192 Mini Edge Server Output Memory Unit 250 node storage 252 Sensor Data Collection Unit 254 sensor data buffers 256 Sensor Data Analysis Unit 300 Node Information Update Unit 302 Node Information DB 304 Vehicle Resource DB 306 Timer 308 Node Number Decision Unit 310 Node Determination Unit 350 Communication Equipment 352 Receiving unit 354 Vehicle Management Department 356 Vehicle information storage unit 358, 902 Alternative Server Vehicle List Creation Department 360 Alternative server vehicle list storage unit 362 Dynamic Map Creation Department 364 Dynamic Map Memory Unit 366 Alternative server vehicle list addition section 368 Transmitter 400, 402, 404, 406, 408, 410, 420, 422, 450, 452, 454, 456, 458, 460, 462, 470, 472, 474, 476, 478, 480, 500, 502, 504, 506, 550, 552, 554, 556, 558, 560, 600, 602, 604, 606, 650, 652, 654, 656, 658, 660, 700, 702, 704, 750, 752, 754, 756, 758, 920, 922, 924, 926, 928, 930, 932, 940, 942, 944, 950, 952 steps 800 Management Area 820, 822, 824 area 830, 832, 834 intersection 850, 870 graph 860, 862, 864, 880, 882, 884 nodes 900 Area Management Department 970 Computer 972, 1342 monitor 974 keyboard 976 Mouse 978 DVD 980 Speaker 982 Microphone 984 USB memory 986, 1200 Network 990 CPU 992 GPU 996 ROM 998 RAM 1000 SSD 1002 DVD drive 1004 Audio I / F 1006 USB port 1008 Network Interface 1010 Bus 1280, 1282, 1284, 1286 Sensor Unit 1290 TCU 1292, 1294, 1296, 1298 Network Switches 1300, 1302 Multi-Gigabit Switch 1330 External communication controller 1332 HMI Controller 1334 Autonomous Driving Controller 1336 Travel controller 1340 Integrated Antenna 1344, 1346, 1350, 1352, 1354, 1356 ECU 1348 Autonomous Driving ECU

Claims

1. a wireless communication device; a driving assistance device for providing driving assistance to a vehicle using assistance information for assisting driving received from an external server via the wireless communication device, the in-vehicle device further comprising: an operation determination unit that determines whether the in-vehicle device should operate in place of the external server in response to receiving a request for distribution of assistance information from another in-vehicle device; an assistance information transmitting device that transmits vehicle assistance information that can be used by the in-vehicle device to the other in-vehicle device via the wireless communication device when the determination by the operation determining unit is affirmative.

2. the assistance information received by the driving assistance device from the external server includes driving assistance information and a list of vehicles that can operate as an alternative server; 2. The in-vehicle device according to claim 1, wherein the operation determination unit includes a list reference unit that references the list and determines whether the in-vehicle device should operate in place of the external server based on whether the vehicle equipped with the in-vehicle device is listed in the list.

3. the in-vehicle device further includes a reception availability determination unit that determines whether the assistance information can be received from the external server via the wireless communication device, 3. The in-vehicle device according to claim 2, wherein the assistance information transmitting device includes a transfer device that transfers the driving assistance information received from the external server to the other in-vehicle device in response to receiving the distribution request for the assistance information from the other in-vehicle device when the determination by the list reference unit is positive and the determination by the reception feasibility determination unit is positive.

4. the in-vehicle device further includes a buffer that stores the distribution requests received from the other in-vehicle devices on a first-in, first-out basis; 4. The in-vehicle device according to claim 3, wherein the transfer device reads the distribution request from the buffer, and ignores the distribution request if the elapsed time from the time of reception of the read distribution request to the current time is longer than a threshold time.

5. the in-vehicle device further includes an internal server that constructs driving assistance information using information available to the in-vehicle device; the support information transmission device, a server initialization unit that initializes and starts the internal server in response to receiving a request for delivery of the support information from an external device when the determination by the list reference unit is affirmative and the determination by the reception possibility determination unit is negative; 4. The in-vehicle device according to claim 3, further comprising: a distribution device that distributes the driving assistance information generated by the internal server to the other in-vehicle device in response to receiving a distribution request for the assistance information from the other in-vehicle device.

6. the in-vehicle device further includes a buffer that stores the distribution requests received from the other in-vehicle devices on a first-in, first-out basis; 6. The in-vehicle device according to claim 5, wherein the distribution device reads the distribution request from the buffer, and ignores the distribution request if the elapsed time from the time of reception of the read distribution request to the current time is longer than a threshold time.

7. 7. The in-vehicle device according to claim 5, wherein the server initialization unit initializes and starts the internal server in response to receiving a plurality of the distribution requests from outside within a most recent predetermined time period, the number of the distribution requests exceeding a predetermined threshold, when the determination by the list reference unit is positive and the determination by the reception feasibility determination unit is negative.

8. The server initialization unit a cooperative node candidate selection unit that selects a plurality of cooperative node candidates from among a plurality of other vehicles that can communicate via the wireless communication device; a processor selection unit for selecting a processor for realizing the functions of the internal server; a dynamic state information acquisition unit that acquires information about a dynamic state related to the selected arithmetic processing device and communication with the arithmetic processing device, and information about a dynamic state related to communication with the outside; an initial information determination unit that selects at least one cooperative node based on the selected cooperative node candidate and the acquired dynamic state, and determines a type of sensor data to be collected from the cooperative node, a vehicle to which the driving assistance information is to be distributed, and a distribution cycle of the driving assistance information; 7. The in-vehicle device according to claim 5, further comprising a transfer unit that transfers the information determined by the initial information determination unit to a storage device of the internal server.

9. 7. The in-vehicle device according to claim 5, further comprising a timer that periodically operates the server initialization unit.

10. 4. The in-vehicle device according to claim 3, further comprising a request sending device that sends a request for distribution of the assistance information to at least one of the vehicles listed on the list when the determination by the list reference unit is negative and the determination by the reception feasibility determination unit is negative.

11. The in-vehicle device according to claim 10 , wherein the request transmitting device transmits the distribution request in order from the top of the list until the assistance information is returned.

12. The in-vehicle device according to claim 11 , wherein the request transmitting device randomly rearranges the list before starting transmission of the distribution request.

13. The in-vehicle device according to claim 10 , wherein the request transmission device randomly selects a vehicle from the list and transmits the distribution request to the selected vehicle.

14. An in-vehicle device as described in any one of claims 1 to 6 and claims 10 to 13, further comprising an information transmission device that, in response to receiving an information distribution request from the external server requesting transmission of information regarding the static specifications and dynamic state of the in-vehicle device, transmits to the external server information regarding the static specifications or dynamic state of the in-vehicle device, as well as information regarding the static specifications or dynamic state of computational resources or communication resources available to the in-vehicle device.

15. a periodic operation determination unit that periodically determines whether the in-vehicle device should operate in place of the external server; 14. The in-vehicle device according to claim 1, further comprising a notification device that notifies the external server of the result of the determination by the periodic operation determination unit when the result of the determination is different from the previous determination.

16. a step of the computer providing driving assistance to the vehicle using assistance information received from the external server via the wireless communication device; a step of determining whether the computer should operate in place of the external server in response to receiving a request for distribution of assistance information from another in-vehicle device; and when the determination in the determination step is positive, the computer transmits the assistance information available to the computer to the other in-vehicle device via the wireless communication device.

17. A computer connected to a wireless communication device, a driving assistance device for providing driving assistance to a vehicle using assistance information received from an external server via the wireless communication device; an operation determination unit that determines whether the computer should operate in place of the external server in response to receiving a request for distribution of assistance information from another in-vehicle device; a computer program causing the computer to function as an assistance information transmitting device that transmits the available assistance information to the other in-vehicle device via the wireless communication device when the determination by the operation determining unit is affirmative;

18. A driving assistance server that creates assistance information to assist driving within a management area and transmits it to a vehicle within the management area, an assistance information creation unit that receives sensor data from a sensor that detects traffic conditions in the management area and creates the assistance information; an alternative server vehicle list creation unit that collects vehicle information about vehicles present within the management area and creates an alternative server vehicle list that is a list of vehicles that can operate as an alternative server for the driving assistance server; a transmitting device that adds the alternative server vehicle list to the assistance information and transmits the information to the vehicle.

19. the alternative server vehicle list creation unit includes a divided area list creation unit that divides the management area into a plurality of divided areas and creates the alternative server vehicle list for each of the plurality of divided areas; 19. The driving assistance server according to claim 18, wherein the transmitting device includes an area-specific transmitting device that, for each of the plurality of divided areas, attaches the alternative server vehicle list for that divided area to the assistance information and transmits the information to each vehicle present in that divided area.

20. A driving assistance method in a driving assistance system including a driving assistance server that creates assistance information for assisting driving within a management area and transmits it to a vehicle within the management area, a step in which a computer receives sensor data from a sensor that detects traffic conditions in the management area and creates the assistance information; a step in which a computer collects vehicle information regarding vehicles present within the management area and creates an alternative server vehicle list, which is a list of vehicles that can operate as an alternative server for the driving assistance server; and a step by a computer adding the alternative server vehicle list to the assistance information and transmitting the information to the vehicle.

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